Some sheet metal parts are formed at elevated temperatures. When appropriately heated the sheet metal workpiece is more ductile and can be stretched without tearing or wrinkling into more complex shapes than can be obtained by stamping at ambient temperature. For example, a sheet metal blank is heated to a stretch forming or blow forming temperature, depending upon the alloy composition and microstructure, and gas pressure is applied to one side of the blank to stretch the blank and force the other side into conformity with the forming surface of a suitable tool.
In one example of elevated temperature sheet metal forming processes, automotive body panel and other sheet metal parts of complex shape are formed from aluminum alloys of superplastically or quick plastically formable composition and metallurgical microstructure. U.S. Pat. No. 6,253,588, entitled “Quick Plastic Forming of Aluminum Alloy Sheet Metal” to Rashid et al, and assigned to the assignee of this invention, describes the forming of some aluminum alloys at high strain rates in the temperature range of, e.g., 825 F to 875 F.
Thus, at the completion of the sheet metal forming step a thin, hot, intricately shaped part must be separated from a hot forming tool without distorting or marring the workpiece. The forming tool is typically carried in a two-part press structure which is opened for removal of the part. The part might be cooled in the opened press before removal from the tool, but such a delay lengthens the manufacturing cycle and is a non-productive use of expensive equipment. Means must be found to carefully remove the soft sheet metal part from the tool for cooling and subsequent trimming or other finishing operation. It is an object of this invention to provide an apparatus associated with the forming tool for accomplishing this task.